It is frequently desired to form metal-containing materials over semiconductor substrates. The metal-containing materials can be incorporated into integrated circuit devices, and/or can be utilized for formation of conductive interconnects between integrated circuit devices.
Copper is a commonly-used conductive material, and is frequently formed over semiconductor substrates for utilization in conductive interconnects. A difficulty in utilizing copper in semiconductor fabrication is that diffusion can occur between copper and various semiconductive materials, including, for example, silicon. Accordingly, barrier layers are often utilized to separate copper from semiconductive materials. Typical barrier layers can include one or more of tungsten, tantalum and titanium. Suitable materials for the barrier layers include, for example, tungsten nitride, tantalum nitride, and/or titanium nitride. Additionally, or alternatively, barrier layers can comprise silicides such as, for example, TiSi2, CoSi2, and chromium silicide.
Although the barrier layers can alleviate or prevent the problem of diffusion between copper and semiconductive materials, the utilization of barrier layers can create new difficulties in semiconductor device fabrication. For instance, it can be difficult to adhere copper to barrier layers.
It is noted that semiconductor processing can comprise formation of metal-containing materials directly on various surfaces without utilizing a barrier layer between the surfaces and the metal-containing materials. For instance, if the metals of the metal-containing materials are so-called noble metals (such as rhodium and iridium, for example), the metal-containing materials can frequently be utilized without barrier layers. Also, if metal-containing materials are deposited on surfaces from which diffusion is unlikely (such as, for example, surfaces comprising Pt or RuO2), barrier layers can be omitted.
It can be desired to incorporate one or more of various metals (such as, for example, copper, platinum, tungsten, rhodium, ruthenium, iridium, gold and nickel) into semiconductor devices. Incorporation of any of the various metals into semiconductor devices can be difficult. It would therefore be desirable to develop new methods for incorporating metal-containing materials into semiconductor constructions.